[BUG] Problems with recurring subtasks that are recreated throught DAVx⁵

[Cyber1000]

Describe the bug
While trying to sync from another tasks-app I found a bug, at least I think so. I've provided a minimal repro with only 2 tasks, to reproduce this. I have a main-task and a sub-task, the sub-task has recurrencies (weekly, but doesn't matter here). It looks like these screenshots (look at the correct indentation and the other parts I marked red, blue are items I've clicked):

Now I remove the calendar within DAVx⁵, therefore also removing the collection from jtxBoard, then I recreate the connection within DAVx⁵ and sync these tasks again. Now the indentation is different, the recurring subtask looks more like a main-task and not a subtask, though the series seems to still have the connection to the main task (but the single entries of the series don't)

To Reproduce

• you need something to sync with DAVx⁵, I use radicale, but I don't think it's the server, since the ics-files look valid.
• you just need to sync to the dav-server, then remove the caldav-entry within DAVx⁵ (and also remove the collection from jxtBoard), rearrange the connection and now sync from server. The result won't be the same.

Expected behavior

• I would expect, that a sync of main+recurring subtasks would exactly recreate when syncing the other way.
• just for info: everything works ok when syncing a main-task owning a non-recurring-subtask

Device and version

• Samsung Galaxy A54
• Android version: Android 11
• jtx Board version: 2.14.1
• Downloaded from: directly from github

[Cyber1000]

The ics-Files on radicale-server look rather normal to me (I've renamed them to md for upload-reasons, but actually they are ics-Files):

maintask.md
recurring-subtask.md

[Cyber1000]

short update: if I complete one of the subtasks, syncing is working again. The problem seems to only exist, if I have a main-task with a sub-task where none of the recurring entries has been completed. If at least one has completed the ics looks like this (having 2 VTODOs, one for the recurrence and one for the completed sub-task):

recurring-subtask-multiple.md